Method of making flexible tubular corrugated metal walls.



W. M. FULTON.

METHOD OF mmrrs FLEXIBLE TUBULAR CORRUGATED METAL WALLS.

APPLlCATlOH FILED DEC. 22, 1913.

Patented Aug. 81, 1915.

2 SHEETSSHEET l.

W. M. FULTON.

METHOD OF MAKING FLEXIBLE TUBULAR CORRUGATED METAL WALLS.

APPLICATION FILED DEC.22, I913.

Patented Aug. 31, 1915.

2 SHEETSSHEET 2.

O u o o a L L w srras earns orrio.

WESTON M. FULTON, OF KNOXVILLE, TENNESSEE, ASSIGNOR TO THE FULTON COM-PANY, OF KNOXVILLE, TENNESSEE, A. CORPORATION OF MAINE.

METHOD OF MAKING FLEXIBLE TUBULAR CORRU(Bl-AT I|J METAL WALLS.

Specification of Letters Patent.

Patented Aug. 311, 19115.

Application filed December 22, 1913. Serial No. 808,240.

To all whom it ma concern:

Be.-,it lmown that I, WESTON M. FULTON,

of Knoxville, Tennessee, have invented a new and useful Improvement inMethods of Making Flexible Tubular Corrugated Metal Walls, whichinvention is fully set forth in the following specification. Thisinvention relates to improvements in methods of making flexible tubularcorrugated metal walls for confining fluids.

Vibratory tubular walls have heretofore been made in one of two generalways, either the wall has been built up of flat annular disks solderedor brazed to each, otherat their edges or a tube was provided withcorrugations sufficiently deep to give to the wall the requisiteflexibility. In the disk construction', flexibility was secured bymaking the width of the annular part quite wide. Whether the meetingedges of the disks were brazed flat together or bent into curved lappedjoints, it was found that the joints did not stand up under thevibratory movements of the wall and cracked apart. The width of thedisks introduced buckling difliculties resulting in lost motion in theextension and contraction of the wall and ex tra wear on the disks.

In the corrugated construction circumferential joints have been avoidedand flexibility secured at the bends as well as in the connectingportions between the bent portions of the wall. This construction hasalso enabled the narrowing of the connecting portions and therebyavoiding in large measure buckling difliculties in these portions. Whilethese advantages have been secured by the introduction of the flexiblecorrugated wall, disadvantages have been introduced especially in thosesituations in which the flexible wall is used to contain an expansiblefluid, the fluctuations of pressure of which on the walls causes thevibratory movement of the wall. In practice, the lateral pressure ofsuch fluid on the wall perpendicular to the axis of the tubular wallbecomes at times excessive and has resulted in the use of non-flexiblebraces which are applied in the form of rings on the concave side of thebends. Such practice is illustrated in U. S. Patent No. 823,382. For thesame purpose the convex sides of the bends have received like braceswhich are recessed curvature of the bends.

to receive the crests-of the bends. While these devices overcome theoutward pressure of the fluid in the vessel, no account has been takenin their use of their effect on the bending strains in the vicinity ofthe wall where they are located. The extension and contraction of acorrugated metal wall is accompanied by changes in the radius of Thepresence of rigid braces either on the concave or on the convex side ofthe bends localizes these bending strains along narrow lines where thewall bends at the brace. Their presence accentuates the wear at thebends in the wall and hastens deterioration at these concave .and convexportions.

- force the bends against fluid pressure forcing them outward and toyieldingly restrainthe flexure of the bends in their vibratory movementeither in one direction or both directions with respect to theirposition of rest and thereby more equally distribute the working strainsbetween the curved portions and lateral portions of the wall andincrease the durability of the wall.

In order that the invention may. be readily understood reference is hadto the accompanyingdrawings which are intended to assist the descriptionand to illustrate some of the ways in which my method may be carriedout. V

"In the drawings :Figure 1 is a view in central vertical section showinga flexible corrugated wall provided with my improvement. Fig. 2 is ahorizontal sectional view taken on line 2-2 of Fig. 1. Figs. 3 and 4 aredetail VleWS highly magnified. Fig. 5 is a View illustrating one mannerof applying the flexible braces to the convex sides of the bends outsideand inside the wall of the tube. Fig. 6 is a view in longitudinalcentral section showing a somewhat different manner of applying thebraces. Figs. 7,

8,9 and are detail views magnified, showing portions of bends to whichdifferent forms of my improved brace are applied.

Referring to Figs. 1, 2, 3 and 4 of the drawings, a'flexible tubularcorrugated wall is therein shown, the bends of which are provided ontheir convex surfaces with braces 1 made of highly resilient material,such as thin sheet brass, steel or the like. In the drawings, thethickness of the metal comprising the walls and. braces is somewhatenlarged for the sake of distinctness. In

practice, very thin metal is used and seldom not more than oneone-hundredth of an inch in thickness. These braces conform to the shapeof the bends and preferably overlap I the marginal surfaces of theportions 2 of the wall which connect the oppositely curved portionsforming the bends of the corrugations. In the form of brace illustratedin Figs. 1-4, gradually increased flexibility isgiven the margins of thebraces 1 by providingthe margins where they extend over the connectingportions 2, with serrations 3. The resiliency of the braces 1.,are thusgrad- .uated along their margins to the degrees of flexure of the bendswhere the latter merge into the lateral connecting portions 2 of thewall, thereby avoiding along these lines sharp lines of wear and moreequally distributing the strains between the curved portions and thelateral connecting portions of the wall during its vibratory movementsand also movements from side to side of its longitudinal axis.

In Fig. 4, a fragment of the corrugated wall is shown while its bend isat .the outward limit of an expansion at of the vessel and while thebend is passing through its normal position of rest, 6. In the position,

a, of expansion, the curved portion of the wall and the brace memberincrease their radii of curvature and a slight slip takes place betweenthe parts. The resilient mar- -gin or serration 3 reinforces the bendwhere 1n contact with it and owing to the marginal resiliency of thebrace continues in contact with the wall to the position of rest 6,thereby hugging the wall in its movements and excluding dirt andmoisture from between the surfaces.

In Figs. 8 and 9, a modified form of resilient brace is shown. Insteadof serrating the margin, the margin is unbroken in outline and thinneddown at 4 and vanishes to an edge. It will be apparent from what hasbeen explained above in respect to the serrated form of brace that thisform accomplishes the same results and in substantially the same manner.

In Fig. 10 is shown a flexible brace in all respects like the two formspreviously described except that serrations and the thinned margin areomitted. While this form does not participate in all theadvantages,.possessed by the other forms in the matter of flexibility,yet it embodies the idea of means for reinforcing the flexiblebends of acorrugated metal wall with a resilient brace which is within the scopeof my invention.

While I have so far described my improvement as applied to the convexsurfaces of the bends in the flexible wall, I may apply the flexiblebrace in any of its forms to either side or to both the convex side andconcave side. This construction is illustrated in Fig. 5 in which aserrated brace 1 is shown on the convex surface of the bend and asimilar brace 1 is shown as placed against the concave surface. Theprinciple of construction is the same for both forms.

The material of the braces is preferably the same as that of which thewalls of the tube are made, yet it is'to be understood that the wall andbraces may be of different material.

It will be observed that all forms of my cumferential curved portions ofthe wall against internal pressureswhile having the other advantagespeculiar to their construction as above pointed out.

The braces may be applied to the tubular.

wall in various ways. Two of such methods are illustrated in Figs. 5 and6.

In accordance with the method indicated in Fig. 5, a flexible corrugatedtubular wall is made preferably in the manner shown and described in myU. S. .Patent 971,838 of Oct. 4, 1910, having broad corrugationstherein. For the purpose of simplifying the description of the method,attention is confined to a single portion of the corrugated tubecontaining a concave and convex portion as it passes through the severalstages indicated in A to G of Fig. 5. A cylindrical ring 1 is made ofresilient material, preferably of the same material as the wall to whichit is to be applied and of a width equal that of the corrugation. In theillustration the margins are provided with serrations. This ring orbrace is of suitable diameter to slip over the outside corrugation andis positioned on the convex side of the bend as shown in stage A whereit may be-soldered to h old it in place though such expedient may beomitted. The corrugation and its '100 resilient brace secure protectionof the ,cir-

external brace 1 are next positioned as at B between a die roll 6 andmatrix roll 7 which are operatively supported by any suitable means, butpreferably the means shown in. my U. S. Patent No. 971,838, are used.Then by closing the rolls 6, 7 on the work, as shown at C, the brace iswrapped around the convex side of the bend in the corrugation. Thisoperation is repeated with another set of rolls to narrow and deepen thecorrugation and to extend the serrated margin of the brace over thelateral portions of the wall connecting the bends. Such step 1s shown atC and may be repeated to further narrow and deepen the corrugations butbefore the bends reach their final dimensions the internal brace 1 isapplied to the convex side of the inner bend. For this purpose a ring 1of metal is inserted into the tube and positioned against an inner bend.Die and matrix rolls 6,7, are applied to the work as in the first stagesof the operation, but 1n this case are reversed in position as shown atE and F. By repeating the applications of these shaping rolls thecorrugations merge into the form indicated at stage G with the braces inposition as shown. This method is equally applicable to any form ofbrace.

in Fig. 6 is illustrated another method of accomplishing the sameresult. The brace rings 1, 1, are applied at intervals both interiorlyand exteriorly on an uncorrugated tube 8 such as a seamed or seamlesstube of resilient metal. These braces are preferably tacked to the wallof the tube by solder and at places which are subsequently to become thecrests of the bends on their convex sides. A series of broad outwardlyextending corrugations 9, are then formed in the tube by a pair of dieand matrix rolls in the manner described in the above U. S. Patent971,838. Two of such corrugations are shown at the right hand end oftube 8, leaving between them a narrow uncorrugated portion 10 which isin width substantially equal the width of the internal brace 1. By meansof a set of narrower rolls these broad corrugations are narrowed anddeepened while bending the brace over the convex surface of the bend. Atthe same time the nar-- row uncorrugated portions 10 are forced inwardand somewhat narrowed and if need be the matrix roll may be placedinside the tube against the interior brace and a companion die rollplaced opposite on the outside to work the inner brace into proper formaround the inner bend. During the final steps of deepening and narrowingthe corrugations the solder loosens its hold considerably and after thewall is in use for a short while, the braces come loose sufiiciently toallow more, or less slippage between the surfaces of the wall and thebrace. This method is equally applicable to any form of brace whetherapplied to the convex or concave surface of the bend, or to both sides.

The degree of resilience to be given the brace will be governed by thedegree of re silience of the particular wall to which it is applied. Forany given wall a brace is selected in form and of material indicated byexperience and test corrugations made with such brace. Then this wall isplaced in a testing machine of any known form adapted to extend andcollapse the bends. An endurance test of this kind reveals whether thelateral portions or the bends give way first. From this data anotherbrace from the same stock is selected of decreased or of increasedstiflness as the data indicates and other braces are made until thecurved and lateral portions of the wall have approximately equaldurability. Having thus determined the particular kind of brace bestsuited for a particular tubular wall, the construction of other walls ofthe same materials is determined thereby.

While I have described my invention as peculiarly applicable to tubularcorrugated walls, I do not desire to limit my application to such wallssince it is applicable to other forms of corrugated walls such as flatcorrugated flexible walls and wherever the bends of flexiblecorrugations are subject to fiexure back and forth.

The article herein described and not claimed forms the subject-matter ofmy U. S. Patent No. 1,096,296, of May 12, 1914, wherein the same isclaimed.

What is claimed is 1. A method of reinforcing corrugations in flexiblecorrugated tubular metal walls, consisting in corrugating a tubularmetal wall, applying resilient metal bands or 1 5 braces to corrugationsof said wall and subjecting said bands or braces to a corrugatingoperation to conform the same to the bends of the corrugations.

2. A method of reinforcing corrugations in flexible corrugated tubularmetal walls, consisting in corrugating a tubular metal wall, applyingseparate resilient metal bands or braces to successive corrugations ofthe wall, and subjecting said bands or braces to a corrugating operationto conform the same to the bends of the corrugations.

3. A method of reinforcing corrugations in flexible corrugated tubularmetal walls, consisting in corrugating a tubular metal 129 wall,applying separate resilient metal bands or braces to the convex bends ofsaid corrugations, and subjecting said bands or braces and wall to afurther corrugating operation to conform said bands or braces to theconvex bends of the corrugations.

1. A method of reinforcing corrugations 1n flex ble corrugated tubularmetal walls, consisting in corrugating a tubular metal wall, applyingseparate resilient metal bands or braces to successive corrugationsspecification in the presence of two subscribof the drvall, cementingsaiid bafilds or braces ing Witnesses. to sai corrugations an su jectingsai bands or braces to a corrugating operation WESTON FULTON 8 toconform the same to the bends of the Witnesses:

corrugations. I. A. MARTIN,.

In testimony whereof I have signed this H. SRMCCOY.

